The present invention relates, in general, to the field of synchronous programmable signal generators and methods. More particularly, the present invention relates to a signal generator and method for high power, low frequency waveform generation in which input 60 hertz power is systematically switched and rectified to produce subharmonic frequencies of the rectified frequency of the 60 hertz input power.
Various requirements exist for relatively high power, low frequency signal generators including motor speed controllers and telephonic applications. In the latter instance, a 20 hertz generator is utilized to provide the ringing signal in standard telephones. Such generators have in the past been relatively complex and expensive, requiring combinations of motors and generators, amplifiers and transformers or high voltage DC power supplies with a square wave drive.
Therefore, a need has existed for a simple and cost effective method for generating low frequency power, particularly an economical ringing generator for small private branch exchange (PBX) type switches. To this end, while conventional 60 hertz power is comparatively economical as a power source, the frequency is inherently unsatisfactory as a ringing frequency.